My 2021 R1250GS has developed what I can best describe as a "thrumming" (oscillating) sound over the past 4-5k miles of a cross US/Canada road trip my wife and I are currently on. I had the 12k mile service done at a BMW dealership in Quebec City, but they didn't have time to really look into it (or test ride it to confirm what I was hearing), but now that we're back in the US I need to get it figured out.
Here are the details of when I can hear the noise as best as I can describe them:
- I've confirmed it's not tire noise; when it's occurring, the sound is the same on dirt/gravel as it is on pavement.
- It's most prominent in the 3rd and 4th gears, although I've heard it in every gear at various times
- It generally starts above 3500 RPMs; it goes away pretty much immediately when I go above 4000 RPMs; I believe this is the most important clue, as I think what is happening is that the sound stops when the ShiftCam shifts from the partial-load to full-load cam. I know nothing about how this works, but given how immediately and consistently the thrumming noise stops when this shift occurs, to me it seems to indicate some sort of timing issue under partial load.
- The thrumming sound isn't occurring 100% of the time; it typically starts when the bike is nice and warmed up (e.g. after an hour or two of riding, but not always--sometimes it happens right after I start riding).
Any theories on what could be happening? I am taking it to a BMW dealership in Missoula, and I'd like to be able to give them some specifics on what I'd like them to take a look at.
Here are the details of when I can hear the noise as best as I can describe them:
- I've confirmed it's not tire noise; when it's occurring, the sound is the same on dirt/gravel as it is on pavement.
- It's most prominent in the 3rd and 4th gears, although I've heard it in every gear at various times
- It generally starts above 3500 RPMs; it goes away pretty much immediately when I go above 4000 RPMs; I believe this is the most important clue, as I think what is happening is that the sound stops when the ShiftCam shifts from the partial-load to full-load cam. I know nothing about how this works, but given how immediately and consistently the thrumming noise stops when this shift occurs, to me it seems to indicate some sort of timing issue under partial load.
- The thrumming sound isn't occurring 100% of the time; it typically starts when the bike is nice and warmed up (e.g. after an hour or two of riding, but not always--sometimes it happens right after I start riding).
Any theories on what could be happening? I am taking it to a BMW dealership in Missoula, and I'd like to be able to give them some specifics on what I'd like them to take a look at.
…may have to try and get a recording of it.
